Question

- When a plastic rod and a metal rod removed from the freezer (same initial temperature) are touched, metal rod is felt cooler than the plastic rod. Why?

2. Does heat flow depend on temperature of the two substances or temperature difference between the substances?

3. Which can be easily heated and cooled? (a) Substance of specific heat capacity = 300 J/kg. C, (b) substance of specific heat capacity = 900 J/kg. C

Answer #1

1.

When you touch metal, its high thermal conductivity allows heat to flow out of your finger and into the metal more quickly than plastic ( which have a low thermal conductivity ). So it pulls more heat away from your finger, so the temperature of your finger changes faster, so it feels colder.

2.

Yes. Heat flow increases with increase in heat flow depend on temperature of the two substances

3.

High Specific Heat means that it takes more energy to raise (or lower) its temperature.

Answer is Substance of **specific heat capacity = 300
J/kg.** C can be cooled easily

A 187 g piece of metal
is rapidly removed from a furnace at a temperature of 600 °C and
quenched in 1600 g of water. The initial temperature of the water
is 25 °C.
If the final
temperature of both metal and water reach 33 °C and knowing that
the specific heat capacity of water is 4190 J kg-1
°C-1, calculate the specific heat capacity of the metal
in J kg-1 °C-1, (to 1 d.p.).
Answer: Answer J
kg-1 °C-1...

500g of water at temperature of 15°C is placed in a
freezer. The freezer has a power rating of 100W and is 80%
efficient.
1- Calculate the energy required to convert the water
into ice at a temperature of -20°C.
2- How much energy is removed every second from the air
in the freezer?
3- How long will it take the water to reach a
temperature of -20°C?
4- Explain the process that cools the air in the
freezer.
5-...

A cube of ice is taken from the freezer at -6.5 ?C and placed in
a 85-g aluminum calorimeter filled with 300 g of water at room
temperature of 20.0 ?C. The final situation is observed to be all
water at 17.0 ?C. The specific heat of ice is 2100 J/kg?C?, the
specific heat of aluminum is 900 J/kg?C?, the specific heat of
water is is 4186 J/kg?C?, the heat of fusion of water is 333 kJ/Kg.
a)What was the...

A cube of ice is taken from the freezer at -5.5 ∘C and placed in
a 85-g aluminum calorimeter filled with 300 g of water at room
temperature of 20.0 ∘C. The final situation is observed to be all
water at 16.0 ∘C. The specific heat of ice is 2100 J/kg⋅C∘, the
specific heat of aluminum is 900 J/kg⋅C∘, the specific heat of
water is is 4186 J/kg⋅C∘, the heat of fusion of water is 333 kJ/Kg.
What was the...

A student doing an experiment pours 0.500 kg of heated metal
whose temperature is 98.0 oC into a 0.356 kg aluminum
calorimeter cup containing 0.418 kg of water at 28.0 °C. The
mixture (and the cup) comes to thermal equilibrium at 38.0 °C. The
specific heat of the metal is ________ J/kg oC.
(specific heat of aluminum = 900 J/kg oC, specific heat
of water = 4186 J/kg oC)

A cube of ice is taken from the freezer at -6.5 ∘C and placed in
a 95-g aluminum calorimeter filled with 300 g of water at room
temperature of 20.0 ∘C. The final situation is observed to be all
water at 16.0 ∘C. The specific heat of ice is 2100 J/kg⋅C∘, the
specific heat of aluminum is 900 J/kg⋅C∘, the specific heat of
water is is 4186 J/kg⋅C∘, the heat of fusion of water is 333
kJ/Kg.
Part A What...

1. You need design a freezer that will keep the temperature
inside a -5.0 C and will operate with a temperature inside at 5.0 C
and will operate in a room with a temperature of 22.0 C. The
freezer is to make 20.0 kg of ice at 0.0 C starting with water at
20.0 C. For water, the specific heat is 4190 J/kg-K, the heat of
fusion is 333 kj/kg.
a. How much energy must be removed from the water...

A cube of ice is taken from the freezer at -8.5 ∘C and placed in
a 85-g aluminum calorimeter filled with 320 g of water at room
temperature of 20.0 ∘C. The final situation is observed to be all
water at 15.0 ∘C. The specific heat of ice is 2100 J/kg⋅C∘, the
specific heat of aluminum is 900 J/kg⋅C∘, the specific heat of
water is is 4186 J/kg⋅C∘, the heat of fusion of water is 333
kJ/Kg.

8.33 kg of steam at temperature of 150 ∘C has 2.23×107 J of heat
removed from it. Determine the final temperature and phase of the
result once the heat has been removed if the heat is removed at
constant pressure during the gas phase. For this problem, use the
specific heat (at constant pressure) for water as 1850 J/kg∘C , the
latent heat of vaporization as 2.256×106 J/kg , the specific heat
of liquid water as 4186 J/kg∘C , the...

A cube of ice is taken from the freezer at -8.5 ∘C and placed in
a 85-g aluminum calorimeter filled with 320 g of water at room
temperature of 20.0 ∘C. The final situation is observed to be all
water at 15.0 ∘C. The specific heat of ice is 2100 J/kg⋅C∘, the
specific heat of aluminum is 900 J/kg⋅C∘, the specific heat of
water is is 4186 J/kg⋅C∘, the heat of fusion of water is 333 kJ/Kg.
What was the...

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